Internal combustion engines combust a fuel and air mixture within cylinders driving pistons to produce drive torque. During engine start-up, the engine operates in transitional modes including key-on, crank, crank-to-run and run. The key-on mode initiates the start-up process and the engine is cranked (i.e., driven by a starter motor) during the crank mode. As the engine is fueled and the initial ignition event occurs, engine operation transitions to the crank-to-run mode. Eventually, when all cylinders are firing and the engine speed is above a threshold level, the engine transitions to the run mode.
Accurate control of fueling plays an important roll in enabling rapid engine start and reduced variation in start time (i.e., the time it takes to transition to the run mode) during the transitional engine start-up. Traditional transitional fuel control systems fail to adequately account for lost fuel and fail to detect and ameliorate misfires and poor-starts during the transitional phases. Further, traditional fuel control systems are not sufficiently robust and require significant calibration effort.